The use of staging solutions in conjunction with graphic arts films of the silver halide type is known. The staging solution effectively permits dot-etching, i.e., the reduction in the size of the halftone, in desired areas while protecting the areas not to be etched. Recently dot-etching of photopolymer elements has become practical. U.S. Pat. No. 4,173,673 discloses dot-etchable masks which are effectively dot etched. Such photopolymer films are different from the silver halide graphic arts films not only in composition but after imagewise exposure and development provide images, e.g., halftone dot or line, which are raised above the support. Commercially available stage solutions utilized in conjunction with the photopolymer elements have been found to be detrimental to the photopolymer image, i.e., they attack the photopolymer layer and image. These staging solutions also have a tendency to flow beyond the point of application thereby preventing etching of a portion of the polymer image which is to be dot etched. Early attempts to make stages for shallow relief images, e.g., the elements of U.S. Pat. No. 4,173,673, were affected by capillary action which resulted in the tendency for the staging solution to spread beyond the area of application, i.e., wicking. Staging solutions with silver halide films are not affected by this problem.
An object of this invention is to provide a process for dot-etching imaged photopolymer layers using a staging solution which does not affect the photopolymer layer or image and remains in the areas of application without spreading or flowing beyond these areas.